Spring RestTemplate GET with parameters

To easily manipulate URLs / path / params / etc., you can use Spring's UriComponentsBuilder class. It's cleaner than manually concatenating strings and it takes care of the URL encoding for you:

HttpHeaders headers = new HttpHeaders();headers.set(HttpHeaders.ACCEPT, MediaType.APPLICATION_JSON_VALUE);UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(url)        .queryParam("msisdn", msisdn)        .queryParam("email", email)        .queryParam("clientVersion", clientVersion)        .queryParam("clientType", clientType)        .queryParam("issuerName", issuerName)        .queryParam("applicationName", applicationName);HttpEntity<?> entity = new HttpEntity<>(headers);HttpEntity<String> response = restTemplate.exchange(        builder.toUriString(),         HttpMethod.GET,         entity,         String.class);

The uriVariables are also expanded in the query string. For example, the following call will expand values for both, account and name:

restTemplate.exchange("http://my-rest-url.org/rest/account/{account}?name={name}",    HttpMethod.GET,    httpEntity,    clazz,    "my-account",    "my-name");

so the actual request url will be

http://my-rest-url.org/rest/account/my-account?name=my-name

Look at HierarchicalUriComponents.expandInternal(UriTemplateVariables) for more details.Version of Spring is 3.1.3.

Since at least Spring 3, instead of using UriComponentsBuilder to build the URL (which is a bit verbose), many of the RestTemplate methods accept placeholders in the path for parameters (not just exchange).

From the documentation:

Many of the RestTemplate methods accepts a URI template and URI template variables, either as a String vararg, or as Map<String,String>.

For example with a String vararg:

restTemplate.getForObject(   "http://example.com/hotels/{hotel}/rooms/{room}", String.class, "42", "21");

Or with a Map<String, String>:

Map<String, String> vars = new HashMap<>();vars.put("hotel", "42");vars.put("room", "21");restTemplate.getForObject("http://example.com/hotels/{hotel}/rooms/{room}",     String.class, vars);

Reference: https://docs.spring.io/spring/docs/current/spring-framework-reference/integration.html#rest-resttemplate-uri

If you look at the JavaDoc for RestTemplate and search for "URI Template", you can see which methods you can use placeholders with.